Abnormal synthesis of mannose 1-phosphate derived carbohydrates in carbohydrate-deficient glycoprotein syndrome type I fibroblasts with phosphomannomutase deficiency.
In fibroblasts from five patients with carbohydrate-deficient glycoprotein syndrome type 1, the incorporation of [2-3H] mannose into mannose phosphates, GDP-mannose, GDP-fucose, dolichol-P-mannose, lipid-linked oligosaccharides, and glycoprotein fraction was determined. We observed a 3- to 5-fold reduction of incorporation of radioactivity into mannose 1-phosphate, GDP-mannose, GDP-fucose, dolichol-P-mannose, and nascent glycoproteins. The incorporation of radioactivity into mannose 6-phosphate was normal. The formation of lipid linked oligosaccharides was only slightly affected (</=20%), but their size was severely reduced, mostly containing five or fewer residues. As a consequence, truncated oligosaccharides were transferred to newly synthesized glycoproteins. The metabolic changes can be explained by a deficiency of phosphomannomutase activity, which was reduced to </=10% of control.
Körner
C
C
Georg-August-Universität, Abt. Biochemie II, Göttingen, Germany.
Lehle
L
L
von Figura
K
K
D002241:Carbohydrates / Q000096:biosynthesis* / Q000172:deficiency; D002478:Cells, Cultured; D018981:Congenital Disorders of Glycosylation / Q000201:enzymology* / Q000378:metabolism* / Q000473:pathology; D004287:Dolichol Monophosphate Mannose / Q000378:metabolism; D005347:Fibroblasts / Q000201:enzymology / Q000378:metabolism; D006154:Guanosine Diphosphate Fucose / Q000096:biosynthesis; D006155:Guanosine Diphosphate Mannose / Q000096:biosynthesis; D006801:Humans; D008070:Lipopolysaccharides / Q000096:biosynthesis; D008360:Mannosephosphates / Q000096:biosynthesis / Q000378:metabolism*; D017875:Phosphotransferases (Phosphomutases) / Q000172:deficiency*
D002241:Carbohydrates; D008070:Lipopolysaccharides; D008360:Mannosephosphates; C023023:lipid-linked oligosaccharides; D006154:Guanosine Diphosphate Fucose; C047217:mannose 1-phosphate; D006155:Guanosine Diphosphate Mannose; D004287:Dolichol Monophosphate Mannose; D017875:Phosphotransferases (Phosphomutases); C052799:phosphomannomutase